Resin composition, method for producing same, and molded article

Abstract

Provided are: a resin composition capable of providing a molded article having excellent wet heat resistance and good mechanical characteristics; a method for producing the resin composition; and a molded article of the resin composition. A resin composition comprising: a polyolefin resin (A) comprising a polypropylene resin (A1) and an acid-modified polypropylene resin (A2) having an acid concentration (in terms of maleic anhydride) (v1) of 0.01-0.5 moL / kg; a regenerated cellulose fiber (B); and an epoxy compound (C) having an epoxy group concentration (f1) of 0.1-6.0 moL / kg, the polyolefin resin (A) content being 25-90 mass% and the regenerated cellulose fiber (B) content being 5-70 mass% with respect to the total mass of the resin composition, and the ratio (R) of the epoxy group concentration in the resin composition to the acid concentration in the resin composition represented by formula (1) being 0.9 or more. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a resin composition, a method for producing the same, and a molded article. Background Art

[0002] Towards building a sustainable society, the effective use of composite resin compositions, which combine biomass components with petroleum-derived resin components, is being promoted. For example, Patent Document 1 proposes a composite resin composition in which plant fibers such as regenerated cellulose fibers are combined with a polypropylene resin.

[0003] In such composite resin compositions, inclusion of a biomass component can be expected to improve mechanical properties such as elastic modulus. However, there is currently no progress in evaluating performance changes and / or detailed studies of issues associated with long-term use of composite resin compositions.

[0004] Patent Document: Japanese Patent Application Laid-Open No. 2011-21087 Summary of the Invention

[0005] The result of the investigation that the present inventor etc. carry out is found, as biomass component, the resistance to moisture and heat of the resin combination that particularly comprises regenerated cellulose fiber is poor." resistance to moisture and heat " is one of the index for judging the deterioration of resin combination in long-term use. After resin combination (or molded product) is carried out wet heat treatment, mechanical properties such as tensile strength and / or flexural strength are compared with before treatment, the degree of deterioration of the resin combination in long-term use can be evaluated thus. The present inventor etc. have carried out research, and the result shows that the resin combination that comprises regenerated cellulose fiber and polypropylene resin whitens, produces strength reduction under wet heat condition, the space growth of regenerated cellulose fiber and resin interface.

[0006] When a polypropylene resin is blended as a resin material, it is often combined with an acid-modified polypropylene resin modified with maleic anhydride or the like. The inventors of the present application conducted further research and discovered that combining this acid-modified polypropylene resin with regenerated cellulose fibers leads to the aforementioned problems. Acid-modified polypropylene resins are often added to improve the adhesion of the polypropylene resin to the fibers. Simply excluding the acid-modified polypropylene resin makes it difficult to achieve the desired mechanical strength.

[0007] Therefore, an object of the present invention is to provide a resin composition capable of providing a molded article having excellent moist heat resistance and good mechanical strength, a method for producing the same, and a molded article of the resin composition.

[0008] The inventors of the present application conducted further studies and found that the reason why the moist heat resistance of the composite resin composition described above is deteriorated is that when a molded article of the resin composition comprising a polypropylene resin, an acid-modified polypropylene resin, and regenerated cellulose fibers is exposed to moist heat conditions, a reaction between the acid-modified polypropylene resin and the cellulose proceeds, thereby promoting the hydrolysis of the resin and / or the cellulose fibers.

[0009] Therefore, the inventors of the present application conducted intensive research and surprisingly discovered that by combining an acid-modified polypropylene resin having an acid concentration (as converted to maleic anhydride) within a certain range with regenerated cellulose fibers, and further compounding an epoxy compound having a specific epoxy group concentration, so that the ratio of the epoxy group concentration in the resin composition to the acid concentration in the resin composition (epoxy group concentration / acid concentration) is 0.9 or greater, the moist heat resistance of the resulting molded article is improved. Furthermore, the molded article obtained from this resin composition also has good mechanical strength.

[0010] That is, the present invention has the following aspects.

[0011] [1] A resin composition, characterized in that the resin composition comprises:

[0012] A polyolefin resin (A) comprising a polypropylene resin (A1) and an acid-modified polypropylene resin (A2), wherein the acid-modified polypropylene resin (A2) is at least one resin selected from a maleic acid-modified polypropylene resin (a1) and a maleic anhydride-modified polypropylene resin (a2), and has an acid concentration (calculated as maleic anhydride) (v1) of 0.01 to 0.5 mol / kg;

[0013] regenerated cellulose fibers (B); and

[0014] Epoxy compound (C) having an epoxy group concentration (f1) of 0.1 to 6.0 mol / kg,

[0015] The content of the polyolefin resin (A) is 25 to 90% by mass, and the content of the regenerated cellulose fiber (B) is 5 to 70% by mass relative to the total mass of the resin composition.

[0016] The ratio (R) of the epoxy group concentration in the resin composition to the acid concentration in the resin composition, represented by the following formula (1), is 0.9 or more.

[0017]

[0018] [2] The resin composition according to [1], wherein the resin composition comprises a regenerated cellulose fiber bundle (B1) impregnated with a polyolefin resin, wherein the regenerated cellulose fiber bundle (B1) impregnated with a polyolefin resin is obtained by impregnating a fiber bundle in which the regenerated cellulose fibers (B) are aligned in the longitudinal direction with a mixture of the polyolefin resin (A) and the epoxy compound (C).

[0019] [3] The resin composition according to [1] or [2], wherein the epoxy compound (C) comprises at least one compound selected from the group consisting of epoxidized oils and fats, epoxy group-containing copolymers, bisphenol-type epoxy compounds, and epoxysilane compounds.

[0020] [4] The resin composition according to any one of [1] to [3], wherein the ratio of the acid-modified polypropylene resin (A2) to the total mass of the polyolefin resin (A) is 0.5 to 5% by mass.

[0021] [5] The resin composition according to any one of [1] to [4], wherein the content of the polyolefin resin (A) is 25 to 90 mass%, the content of the regenerated cellulose fiber (B) is 5 to 70 mass%, and the content of the epoxy compound (C) is 0.05 to 5 mass%, relative to the total mass of the resin composition.

[0022] [6] The resin composition according to any one of [1] to [5], wherein the acid-modified polypropylene resin (A2) comprises the maleic anhydride-modified polypropylene resin (a2).

[0023] [7] The resin composition according to any one of [1] to [6], wherein the epoxy compound (C) contains at least one compound selected from the group consisting of epoxy group-containing copolymers and bisphenol-type epoxy compounds.

[0024] [8] The resin composition according to any one of [1] to [7], wherein the average fiber length of the regenerated cellulose fiber (B) in the resin composition is 5 to 30 mm.

[0025] [9] A molded article of the resin composition according to any one of [1] to [8].

[0026]

[10] The method for producing a resin composition according to any one of [1] to [8], comprising the following steps:

[0027] obtaining a mixture of the polyolefin resin (A) and the epoxy compound (C); and compounding the mixture with the regenerated cellulose fiber (B),

[0028] The operation of obtaining the mixture includes: mixing the polyolefin resin (A) and the epoxy compound (C) so that the ratio (R) of the epoxy group concentration in the final resin composition to the acid concentration in the final resin composition represented by the following formula (1) is 0.9 or more.

[0029]

[0030] According to the present invention, there can be provided a resin composition capable of providing a molded article having excellent moist heat resistance and good mechanical strength, a method for producing the same, and a molded article of the resin composition. DETAILED DESCRIPTION

[0031] Hereinafter, an embodiment of the present invention will be described in detail, but the scope of the present invention is not limited to the embodiment described herein, and various changes can be made within the scope of the present invention. In addition, with respect to a specific parameter, when multiple upper limits and lower limits are recorded, any upper limit and lower limit among these upper limits and lower limits can be combined to form an appropriate numerical range. In addition, in this specification, the description of "X to Y" means "above X and below Y". For example, "10 to 50% by mass" means "above 10% by mass and below 50% by mass".

[0032] [Resin composition]

[0033] The resin composition of the present embodiment comprises: a polyolefin resin (A) comprising a polypropylene resin (A1) and an acid-modified polypropylene resin (A2), wherein the acid-modified polypropylene resin (A2) is at least one resin selected from a maleic acid-modified polypropylene resin (a1) and a maleic anhydride-modified polypropylene resin (a2), and has an acid concentration (in terms of maleic anhydride) (v1) of 0.01 to 0.5 mol / kg; regenerated cellulose fiber (B); and an epoxy compound (C) having an epoxy group concentration (f1) of 0.1 to 6.0 mol / kg.

[0034] The content of the polyolefin resin (A) is 25 to 90% by mass, and the content of the regenerated cellulose fiber (B) is 5 to 70% by mass relative to the total mass of the resin composition.

[0035] The ratio (R) of the epoxy group concentration in the resin composition to the acid concentration in the resin composition, represented by the following formula (1), is 0.9 or more.

[0036]

[0037] According to the resin composition of this embodiment, a molded article having excellent moist heat resistance and good mechanical strength can be provided.

[0038] The resin composition of the present embodiment has a ratio (R) of the epoxy group concentration in the resin composition to the acid concentration in the resin composition (hereinafter referred to as "ratio (R)") represented by the above formula (1) and is 0.9 or more. In one embodiment, the ratio (R) is preferably 1.0 or more, more preferably 1.5 or more, and further preferably 2.0 or more. The upper limit of the ratio (R) is not particularly limited, and from the viewpoint of the dispersibility of the epoxy compound (C) in the resin composition, it may be 5.0 or less, or 4.0 or less. In a preferred embodiment, the ratio (R) may be 0.9 to 5.0, 1.0 to 5.0, 1.5 to 4.0, or 1.6 to 3.1. It should be noted that, as shown in formula (1), the acid concentration in the resin composition (equivalent to the value of the denominator of formula (1)) can be calculated by multiplying the mass (kg / kg) of the acid-modified polypropylene resin (A2) in 1 kg of the resin composition by the acid concentration (v1) (moL / kg). Similarly, the epoxy group concentration in the resin composition (the value corresponding to the numerator of formula (1)) can be calculated by multiplying the mass (kg / kg) of the epoxy compound (C) in 1 kg of the resin composition by the epoxy group concentration (f1) (moL / kg).

[0039] <Polyolefin resin (A)>

[0040] The resin composition of this embodiment may include a polyolefin resin (A) containing a polypropylene resin (A1) and an acid-modified polypropylene resin (A2). The content of the polyolefin resin (A) is 25 to 90% by mass relative to the total mass of the resin composition. The content of the polyolefin resin (A) (hereinafter sometimes referred to as "resin (A)") in the resin composition can be arbitrarily adjusted within the range of 25 to 90% by mass and within the range of a ratio (R) of 0.9 or greater.

[0041] (Polypropylene resin (A1))

[0042] The resin (A) of this embodiment comprises a polypropylene resin (A1). Examples of the polypropylene resin (A1) (hereinafter sometimes referred to as "resin (A1)") include propylene homopolymers (hereinafter sometimes referred to as "PP homopolymers") and copolymers of propylene and α-olefins other than propylene. It should be noted that the resin (A1) does not include polypropylene resins modified with maleic acid or maleic anhydride, as described below.

[0043] Examples of the propylene homopolymer include isotactic polypropylene and syndiotactic polypropylene, of which one type may be used alone or two or more types may be used in combination.

[0044] Examples of α-olefins other than propylene include ethylene, butene, hexene, and heptene. These may be used alone or in combination of two or more. Among these, preferred copolymers of propylene and α-olefins other than propylene are block copolymers of propylene and ethylene, and random copolymers of propylene and ethylene.

[0045] In one embodiment, the resin (A1) preferably comprises at least one resin selected from the group consisting of a PP homopolymer, a block copolymer of propylene and ethylene (hereinafter sometimes referred to as a "PP block copolymer"), and a random copolymer of propylene and ethylene, and more preferably comprises at least one resin selected from the group consisting of a PP homopolymer and a PP block copolymer.

[0046] In one embodiment, as the resin (A1), a polypropylene resin having a melt flow rate (MFR) (230° C., 2.16 kg load) measured in accordance with ISO 1133 of 20 to 300 g / 10 min can be used.

[0047] In one embodiment, the ratio of the resin (A1) in the resin (A) can be 90 to 99.95% by mass, 93 to 99.95% by mass, 95 to 99.95% by mass, 97 to 99.95% by mass, or 99 to 99.92% by mass relative to the total mass of the resin (A). In one embodiment, the ratio of the resin (A1) in the resin (A) can be 97 to 98.5% by mass. If the ratio of the resin (A1) in the resin (A) is within the above range, it is easy to adjust the acid concentration in the resin composition, and it is easy to become a resin composition with a ratio (R) of 0.9 or more.

[0048] In one embodiment, the ratio of the resin (A1) in the resin composition can be 22.5 to 89.5 mass %, 35 to 89.5 mass %, 50 to 89.5 mass %, 60 to 89.5 mass %, or 65 to 70 mass % relative to the total mass of the resin composition.

[0049] (Acid-modified polypropylene resin (A2))

[0050] The resin (A) of this embodiment comprises an acid-modified polypropylene resin (A2), wherein the acid-modified polypropylene resin (A2) is at least one resin selected from a maleic acid-modified polypropylene resin (a1) and a maleic anhydride-modified polypropylene resin (a2), and has an acid concentration (maleic anhydride equivalent) (v1) of 0.01 to 0.5 mol / kg.

[0051] By combining an acid-modified polypropylene resin (A2) (hereinafter sometimes referred to as "resin (A2)") having an acid concentration (v1) in the range of 0.01 to 0.5 mol / kg with an epoxy compound (C) described below, and adjusting the ratio (R) in the resin composition to 0.9 or greater, a molded article having excellent moist heat resistance and good mechanical strength can be obtained. It should be noted that the "acid concentration (v1)" refers to the value of the raw material resin (A2), and the manufacturer's nominal value can be used.

[0052] In one embodiment, from the perspective of easily adjusting the ratio (R) in the resin composition to 0.9 or more, the acid concentration (v1) of the resin (A2) can be 0.01 to 0.21 mol / kg, 0.01 to 0.11 mol / kg, or 0.10 to 0.21 mol / kg. Alternatively, the acid concentration (v1) can be 0.11 to 0.5 mol / kg, or 0.2 to 0.5 mol / kg. The acid concentration (v1) of the resin (A2) can be controlled by adjusting the degree of modification (acid value) of maleic acid and / or maleic anhydride in the maleic acid-modified polypropylene resin (a1) and / or maleic anhydride-modified polypropylene resin (a2).

[0053] (Maleic acid-modified polypropylene resin (a1), maleic anhydride-modified polypropylene resin (a2))

[0054] The resin (A2) of this embodiment is at least one resin selected from a maleic acid-modified polypropylene resin (a1) (hereinafter sometimes referred to as "resin (a1)") and a maleic anhydride-modified polypropylene resin (a2) (hereinafter sometimes referred to as "resin (a2)").

[0055] In a preferred embodiment, resins (a1) and (a2) can be acid-modified polypropylene resins obtained by graft-polymerizing maleic acid or maleic anhydride onto polypropylene. The polypropylene in resins (a1) and (a2) can be a PP homopolymer or a PP block copolymer.

[0056] In one embodiment, commercially available products can be used for resin (a1) and resin (a2). Examples of commercially available products include "MODIC (registered trademark) P 908" (acid concentration (v1): 0.11 mol / kg) manufactured by Mitsubishi Chemical Group Corporation, "OREVAC (registered trademark) CA100" (acid concentration (v1): 0.11 mol / kg) manufactured by SK Functional Polymer Co., Ltd., and "POLYBOND (registered trademark) 3200" (acid concentration (v1): 0.21 mol / g) manufactured by SI Group. These resins (a1) and (a2) may be used alone or in combination of two or more.

[0057] In one embodiment, the resin (A2) can be a resin having an acid concentration (v1) of 0.01 to 0.5 mol / kg and an MFR (190°C, 2.16 kg load) of 50 g / 10 min or greater. An MFR (190°C, 2.16 kg load) of 50 g / 10 min or greater is preferred because the dispersibility of the resin is easily improved.

[0058] In one embodiment, the ratio of the resin (A2) in the resin (A) can be 0.05 to 10 mass %, 0.05 to 7 mass %, 0.05 to 5 mass %, 0.05 to 3 mass %, or 0.08 to 1 mass % relative to the total mass of the resin (A). In one embodiment, the ratio of the resin (A2) in the resin (A) can be 1.5 to 3 mass % relative to the total mass of the resin (A). If the ratio of the resin (A2) in the resin (A) is within the above range, it is easy to adjust the acid concentration in the resin composition, and it is easy to become a resin composition with a ratio (R) of more than 0.9. In addition, when the resin (A2) includes the resin (a2), the ratio of the resin (a2) in the resin (A) can be set to the same range as the ratio of the aforementioned resin (A2). That is, the proportion of resin (a2) in resin (A) can be 0.05 to 10 mass %, 0.05 to 7 mass %, 0.05 to 5 mass %, 0.05 to 3 mass %, 0.08 to 1 mass %, or 1.5 to 3 mass % relative to the total mass of resin (A).

[0059] In one embodiment, from the perspective of easily adjusting the ratio (R) to 0.9 or greater, the acid concentration in the resin composition may be 0.05 to 3.0 mmoL / kg, 0.05 to 2.6 mmoL / kg, 0.05 to 1.0 mmoL / kg, or 0.05 to 0.5 mmoL / kg. Alternatively, the acid concentration may be 1.1 to 2.4 mmoL / kg.

[0060] (Other polyolefin resins)

[0061] In one embodiment, the resin (A) may contain a resin (other polyolefin resin) other than the resin (A1) and the resin (A2).

[0062] The other polyolefin resins are not particularly limited as long as they exhibit the effects of the present invention. Examples thereof include homopolymers or copolymers of olefins having 2 to 6 carbon atoms other than resins (A1) and resin (A2) (ethylene resins such as polyethylene and ethylene-propylene copolymers; poly(methylpentene-1); propylene-methylpentene copolymers; copolymers of olefins having 2 to 6 carbon atoms and comonomers (ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylate copolymers); homopolymers or copolymers of cyclic olefins (particularly cyclic olefins fused to hydrocarbon rings, bridged cyclic olefins, etc.) which may have substituents such as alkyl and / or ester groups (e.g., homopolymers of cyclic olefins such as polydicyclopentadiene and polynorbornene; copolymers of cyclic olefins selected from bicycloalkanedienes, tricycloalkanedienes, bicycloolefins, and tricycloolefins with α-olefins having 2 to 4 carbon atoms (e.g., ethylene)); and the like. These may be used alone or in combination of two or more.

[0063] When the resin (A) contains other polyolefin resins, the amount thereof can be arbitrarily adjusted so that the ratio (R) of the finally obtained resin composition is 0.9 or more, but is preferably 50% by mass or less relative to the total mass of the resin (A).

[0064] In addition, the resin (A) may contain a thermoplastic resin other than the above-mentioned resin (A1), resin (A2) and other polyolefin resins as an optional component within the range of a ratio (R) of 0.9 or more in the final resin composition, and the content thereof is preferably 20% by mass or less relative to the total mass of the resin (A).

[0065] <Regenerated cellulose fiber (B)>

[0066] The resin composition of the present embodiment includes regenerated cellulose fiber (B). The content of the regenerated cellulose fiber (B) in the resin composition is 5 to 70 mass % relative to the gross mass of the resin composition. From the viewpoint of the manufacturability of pellets and / or molded articles, the content of the regenerated cellulose fiber (B) in the resin composition can be 10 to 60 mass %, can be 10 to 50 mass %, or can be 10 to 40 mass % relative to the gross mass of the resin composition. In one embodiment, the content of the regenerated cellulose fiber (B) in the resin composition can be 40 to 70 mass %, can be 50 to 70 mass %, or can be 60 to 70 mass % relative to the gross mass of the resin composition.

[0067] In this specification, "regenerated cellulose fibers" refer to cellulose fibers obtained by artificial spinning using natural cellulose fibers (cellulose fibers derived from higher plants, cellulose fibers derived from animals, and cellulose fibers derived from bacteria) and / or chemically synthesized cellulose fibers.

[0068] Examples of cellulose fibers derived from higher plants include natural cellulose fibers (pulp fibers) such as wood fibers (wood pulp from coniferous trees, broadleaf trees, etc.), bamboo fibers, sugarcane fibers, seed hair fibers (cotton linters, bombax cotton, kapok, etc.), bast fibers (for example, hemp, paper mulberry, and daphne), and leaf fibers (for example, Manila hemp and New Zealand hemp).

[0069] Examples of animal-derived cellulose fibers include ascidian cellulose and the like.

[0070] Examples of chemically synthesized cellulose fibers include organic acid esters such as cellulose acetate (cellulose acetate), cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate; inorganic acid esters such as cellulose nitrate, cellulose sulfate, and cellulose phosphate; mixed acid esters such as cellulose nitrate acetate; hydroxyalkyl cellulose (such as hydroxyethyl cellulose (HEC), hydroxypropyl cellulose, etc.); carboxyalkyl cellulose (such as carboxymethyl cellulose (CMC), carboxyethyl cellulose, etc.); alkyl cellulose (such as methyl cellulose and ethyl cellulose); and cellulose derivatives such as regenerated cellulose (such as rayon and cellophane).

[0071] These natural cellulose fibers and chemically synthesized cellulose fibers may be used alone or in combination of two or more.

[0072] As a method for obtaining regenerated cellulose fibers from the above-mentioned cellulose fibers, for example, a viscose method, a cuprammonia method, a solvent spinning method (a direct method in which cellulose is not temporarily chemically converted), etc. can be cited. As regenerated cellulose fibers obtained by the viscose method, viscose rayon, Polynosic, Modal, etc. can be cited. In addition, as regenerated cellulose fibers obtained by the cuprammonia method, cuprammonia fibers, etc. can be cited. In addition, as regenerated cellulose fibers obtained by the solvent spinning method, lyocell, Tencel, etc. can be cited. As the regenerated cellulose fiber (B), one of these regenerated cellulose fibers can be used alone, or two or more can be used in combination.

[0073] In one embodiment, the regenerated cellulose fibers (B) preferably include regenerated cellulose fibers obtained by the viscose process, and more preferably include viscose rayon. When the regenerated cellulose fibers (B) include regenerated cellulose fibers obtained by the viscose process, the mechanical strength of the resulting molded article is likely to be improved.

[0074] In one embodiment, the average fiber diameter of the regenerated cellulose fibers (B) is preferably 5 to 30 μm, and the X-ray orientation is preferably 86% or greater. These average fiber diameters and X-ray orientations facilitate impregnation of the regenerated cellulose fibers (B) with the resin (A). Furthermore, the mechanical strength of the resulting molded article is also readily improved.

[0075] The average fiber diameter is more preferably 6 to 20 μm, and even more preferably 7 to 15 μm. The average fiber diameter of the regenerated cellulose fibers (B) can be calculated from the average value of the diameters (major diameters) of a plurality of fibers observed by SEM or the like.

[0076] The X-ray orientation degree is more preferably 90% or more. The X-ray orientation degree of the regenerated cellulose fiber (B) can be determined according to the formula described in Japanese Patent Application Laid-Open No. 9-31744 and / or Japanese Patent Application Laid-Open No. 9-256216.

[0077] In one embodiment, the tensile modulus (Young's modulus) of the regenerated cellulose fiber (B) may be 10 GPa or greater, 13 GPa or greater, or even 15 GPa or greater. The tensile modulus of the regenerated cellulose fiber (B) can be determined by the method described in paragraph 0038 of JP-A-2013-91775, "After storage for 3 weeks in an air-conditioned environment at 23°C and 50% RH, the fiber is measured at a chuck distance of 200 mm and a tensile speed of 200 mm / min."

[0078] In one embodiment, long fibers are preferably used as the regenerated cellulose fibers (B). When long fibers are used as the regenerated cellulose fibers (B), the average fiber length of the regenerated cellulose fibers (B) in the resin composition is preferably 5 to 30 mm, more preferably 5 to 15 mm, and even more preferably 5 to 10 mm. By including such regenerated cellulose fibers (B), the mechanical strength of the molded article obtained by injection molding is easily further improved.

[0079] In one embodiment, the resin composition may include a polyolefin resin-impregnated regenerated cellulose fiber bundle (B1), which is composed of a fiber bundle formed by aligning and bundling regenerated cellulose fibers (B) impregnated with resin (A) in the longitudinal direction. That is, the resin composition of this embodiment may be composed of a polyolefin resin-impregnated regenerated cellulose fiber bundle (B1) containing resin (A) and regenerated cellulose fibers (B) and an epoxy compound (C) described below. In a preferred embodiment, the polyolefin resin-impregnated regenerated cellulose fiber bundle (B1) may be a fiber bundle obtained by impregnating regenerated cellulose fibers (B) with a mixture containing resin (A) and epoxy compound (C). The details of the polyolefin resin-impregnated regenerated cellulose fiber bundle (B1) are described below.

[0080] (Regenerated cellulose fiber bundle impregnated with polyolefin resin (B1))

[0081] The polyolefin resin-impregnated regenerated cellulose fiber bundle (B1) (hereinafter sometimes referred to simply as "fiber bundle (B1)") is a composite material obtained by impregnating a fiber bundle in which regenerated cellulose fibers (B) are aligned in the longitudinal direction with the resin (A) and then cutting the fiber bundle. In a preferred embodiment, the composite material may be obtained by impregnating the fiber bundle with a mixture of an epoxy compound (C) and the resin (A), which will be described later, and then cutting the fiber bundle. In this embodiment, the fiber bundle (B1) includes a fiber bundle impregnated with the resin (A) and a fiber bundle impregnated with a mixture of the resin (A) and the epoxy compound (C) (hereinafter sometimes referred to simply as "the mixture").

[0082] In one embodiment, the average fiber length of the regenerated cellulose fibers (B) in the fiber bundle (B1) may be 5 to 30 mm, 5 to 15 mm, or even 5 to 10 mm. It should be noted that the fiber length of the regenerated cellulose fibers (B) in the fiber bundle (B1) is the same as the length of the major axis of the fiber bundle (B1). Therefore, the average fiber length can be calculated by measuring the lengths of the major axes of approximately 100 pellets of the fiber bundle (B1) using a vernier caliper or the like, and averaging the measured values.

[0083] The number of regenerated cellulose fibers (B) in the fiber bundle (B1) is preferably 2,000 to 30,000, more preferably 3,000 to 25,000, and even more preferably 5,000 to 25,000. If the number of regenerated cellulose fibers (B) is within the above range, the resin (A) (or mixture) easily penetrates into the center of the fiber bundle (B1). As a result, when the resin composition containing the fiber bundle (B1) is molded, it is easy to obtain a molded product with a better appearance and better mechanical strength. In addition, when manufacturing the fiber bundle (B1), it is not easy to produce manufacturing problems such as fiber bundle breakage.

[0084] In one embodiment, the fiber bundle (B1) can be produced by a known production method using a mold. Specifically, the production methods described in Japanese Patent Application Laid-Open No. 6-313050, Japanese Patent Application Laid-Open No. 2007-176227, Japanese Patent Application No. 6-2344, etc. can be applied.

[0085] In one embodiment, when the fiber bundle (B1) is composed of a resin (A) and regenerated cellulose fibers (B), the ratio of the regenerated cellulose fibers (B) to the total mass of the fiber bundle (B1) is preferably 5 to 70% by mass, more preferably 10 to 60% by mass, further preferably 10 to 50% by mass, and particularly preferably 10 to 40% by mass. In addition, the ratio of the resin (A) in the fiber bundle (B1) is preferably 30 to 95% by mass, more preferably 50 to 90% by mass, further preferably 60 to 90% by mass, and particularly preferably 60 to 80% by mass. By adjusting the ratio of the regenerated cellulose fibers (B) to the total mass of the fiber bundle (B1) to within the above range, the fluidity during injection molding and the mechanical strength of the molded article are easily improved. It should be noted that, when the fiber bundle (B1) is composed of a mixture and regenerated cellulose fibers (B), the ratio of the regenerated cellulose fibers (B) in the fiber bundle (B1) can also be arbitrarily adjusted within the aforementioned range. The ratio of the resin (A) is also the same.

[0086] In one embodiment, the fiber bundle (B1) may contain known flame retardants and flame retardant aids, heat stabilizers, lubricants, light stabilizers, antioxidants, colorants, release agents, antistatic agents, etc., within a range that does not hinder the effects of the present invention.

[0087] <Epoxy Compound (C)>

[0088] The resin composition of the present embodiment contains an epoxy compound (C) having an epoxy group concentration (f1) of 0.1 to 6.0 mol / kg. By combining such an epoxy compound (C) with a resin (A) and a regenerated cellulose fiber (B), and adjusting the ratio (R) in the resin composition to 0.9 or more, a molded product having excellent resistance to moisture and heat can be obtained. In addition, the mechanical strength of the obtained molded product is also good. It should be noted that the "epoxy group concentration (f1)" is the value of the epoxy compound (C) of the raw material, and the manufacturer's nominal value can be used.

[0089] In one embodiment, from the perspective of easily achieving a ratio (R) of 0.9 or greater in the resin composition, the epoxy group concentration (f1) may be 0.1 to 5.0 mol / kg, 0.1 to 4.5 mol / kg, or 0.2 to 4.2 mol / kg. Alternatively, the epoxy group concentration (f1) may be 1.0 to 6.0 mol / kg, 1.7 to 6.0 mol / kg, or 1.7 to 5.2 mol / kg.

[0090] The epoxy compound (C) is not particularly limited as long as the epoxy group concentration (f1) is within the above range, and conventionally known epoxy compounds can be used. From the perspectives of cost and handling, the epoxy compound (C) preferably comprises at least one compound selected from the group consisting of epoxidized oils and fats, epoxy group-containing copolymers, bisphenol-type epoxy compounds, and epoxysilane compounds, and more preferably comprises at least one compound selected from the group consisting of epoxy group-containing copolymers and bisphenol-type epoxy compounds, having an epoxy group concentration (f1) of 0.1 to 6.0 mol / kg.

[0091] As epoxidized fats and oils, for example, epoxidized triglycerides and epoxidized fatty acid monoesters can be used. Examples of epoxidized triglycerides include epoxidized soybean oil and epoxidized linseed oil. In addition, the alkyl group (R2) in the alkyl ester portion of the epoxidized fatty acid monoester (R1COOR2) can be, for example, a linear or branched alkyl group having 4 to 12 carbon atoms. More specifically, examples include epoxidized fatty acid butyl ester and epoxidized fatty acid octyl ester. These epoxidized fats and oils can be used alone or in combination of two or more. Among them, epoxidized soybean oil is preferably used from the viewpoint of price and operability. It should be noted that commercially available products can be used as epoxidized fats and oils having an epoxy group concentration (f1) of 0.1 to 6.0 mol / kg. Examples of commercially available products include "Adekacizer (registered trademark) O-130P" (epoxy group concentration (f1): 4.2 mol / kg) manufactured by ADEKA CORPORATION.

[0092] Examples of the epoxy-containing copolymer include at least one selected from the group consisting of epoxy-containing olefin polymers (hereinafter sometimes referred to as "polymer (I)") and epoxy-containing styrene polymers (hereinafter sometimes referred to as "polymer (II)").

[0093] Examples of the polymer (I) include copolymers composed of repeating units derived from an α-olefin and repeating units derived from a glycidyl ester of an α,β-unsaturated acid.

[0094] The α-olefin is not particularly limited, and examples thereof include ethylene, propylene, and butene. Among them, ethylene is preferably used.

[0095] The glycidyl ester of an α,β-unsaturated acid refers to a compound represented by the following general formula (2). In the following general formula (2), R' represents hydrogen, a linear or branched lower alkyl group having 1 to 5 carbon atoms, or an -R3-COOH group (R3 represents a linear or branched alkylene group having 1 to 5 carbon atoms). Among them, the glycidyl ester of an α,β-unsaturated acid is preferably glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, or glycidyl itaconate. From the viewpoint of price and handleability, glycidyl methacrylate is particularly preferably included.

[0096]

[0097] In one embodiment, polymer (I) may contain, in addition to the two components described above, one or more repeating units derived from olefinic unsaturated esters such as acrylonitrile, acrylate, methacrylate, and α-methylstyrene as a third component, within a range not impairing the effects of the present invention. When the third component is included, any amount may be added within the range of 0.1 to 6.0 mol / kg of the epoxy group concentration (f1) of polymer (I).

[0098] Polymer (I) can be prepared by conventional free radical polymerization using monomers corresponding to the above-mentioned components and a free radical polymerization catalyst. Specifically, it can be produced by copolymerizing an α-olefin with a glycidyl ester of an α,β-unsaturated acid in the presence of a free radical polymerization catalyst at 500 to 4000 atmospheres and 100 to 300°C. The above polymerization can be carried out in the presence or absence of a solvent and / or a chain transfer agent. Alternatively, it can be produced by mixing an α-olefin with a glycidyl ester of an α,β-unsaturated acid and a free radical polymerization catalyst and performing melt graft copolymerization in an extruder.

[0099] Examples of polymer (II) include copolymers composed of repeating units derived from styrenes and repeating units derived from glycidyl esters of α,β-unsaturated acids. Examples of glycidyl esters of α,β-unsaturated acids are the same as those for polymer (I), and preferred examples are also the same.

[0100] Examples of the styrenes include styrene, α-methylstyrene, halogenated styrenes (eg, brominated styrene), and divinylbenzene. Among these, styrene is preferably used.

[0101] In one embodiment, in polymer (II), in addition to the above two components, a third component may be a multi-component copolymer containing one or more repeating units derived from other vinyl monomers, within the range that does not impair the effects of the present invention. Suitable third components are one or more repeating units derived from olefinic unsaturated esters such as acrylonitrile, acrylate, and methacrylate. When a third component is included, any amount may be added within the range of 0.1 to 6.0 mol / kg of the epoxy group concentration (f1) of polymer (II).

[0102] Polymer (II) can be prepared by conventional free radical polymerization using monomers corresponding to the above components and a free radical polymerization catalyst. Specifically, it can be produced by copolymerizing styrenes with glycidyl esters of α,β-unsaturated acids in the presence of a free radical polymerization catalyst at 500 to 4000 atmospheres and 100 to 300°C. The polymerization can be carried out in the presence or absence of a solvent and / or a chain transfer agent. Alternatively, it can be produced by mixing an α-olefin with a glycidyl ester of an α,β-unsaturated acid and a free radical polymerization catalyst and performing melt graft copolymerization in an extruder.

[0103] In one embodiment, from the viewpoint that the heat resistance of the obtained molded article is likely to be further improved and the moist heat resistance is also likely to be improved, it is preferred to include a polymer (I), more preferably a polymer (I) containing an acrylic acid ester as the third component, and particularly preferably ethylene-glycidyl methacrylate-methyl acrylate.

[0104] In addition, when using polymer (I) and polymer (II) together, the ratio between these polymers can be appropriately adjusted according to the required properties.

[0105] Preferred examples of bisphenol-type epoxy compounds include bisphenol A-type epoxy compounds, bisphenol F-type epoxy compounds, and bisphenol AD-type epoxy compounds. Among these, bisphenol A-type epoxy compounds and bisphenol F-type epoxy compounds are more preferred from the perspectives of price and handling, and bisphenol A-type epoxy compounds are particularly preferred. Bisphenol-type epoxy compounds may be used alone or in combination of two or more.

[0106] Examples of the epoxysilane compound include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Epoxysilane compounds may be used alone or in combination of two or more.

[0107] In one embodiment, the epoxy compound (C) particularly preferably comprises at least one compound selected from epoxidized soybean oil, ethylene-glycidyl methacrylate-methyl acrylate, and bisphenol A epoxy compounds, having an epoxy group concentration (f1) of 0.1 to 6.0 mol / kg.

[0108] In one embodiment, from the perspective of easily adjusting the ratio (R) to 0.9 or more, the ratio of the epoxy compound (C) contained in the resin composition is preferably 0.05 to 5% by mass, more preferably 0.05 to 4% by mass, even more preferably 0.05 to 3% by mass, and particularly preferably 0.08 to 2% by mass relative to the total mass of the resin composition. Furthermore, the epoxy group concentration in the resin composition is preferably 2.0 to 6.8 mmol / kg, more preferably 2.0 to 5.5 mmol / kg, and even more preferably 2.1 to 5.0 mmol / kg.

[0109] <Other ingredients>

[0110] In the resin combination of the present embodiment, the composition (other components) other than above-mentioned resin (A), regenerated cellulose fiber (B) and epoxy compound (C) can be included in the scope of not hindering the effect of the present invention. As other components, for example, softener, surface lubricant, leveling agent, antioxidant, surfactant, corrosion inhibitor, light stabilizer, ultraviolet absorber, heat stabilizer, polymerization inhibitor, silane coupling agent (except epoxy silane compound), lubricant, plasticizer, crystallization accelerator, hydrolysis inhibitor, inorganic filler, organic filler, metal powder, pigment etc. other than plant origin can be listed. They can be used alone or with two or more. In the case where resin combination includes other components, relative to the gross mass of resin combination, it can be set to less than 1 mass %.

[0111] <Method for producing resin composition>

[0112] The resin composition of the present embodiment is manufactured by the following method, which includes the following operations: obtaining a mixture of a polyolefin resin (A) and the aforementioned epoxy compound (C), and mixing the aforementioned mixture into regenerated cellulose fiber (B), the operation of obtaining the aforementioned mixture includes: mixing the polyolefin resin (A) and the epoxy compound (C) so that the ratio (R) of the epoxy group concentration in the finally obtained resin composition represented by the following formula (1) to the acid concentration in the finally obtained resin composition is 0.9 or more.

[0113]

[0114] Examples of a method for mixing the polyolefin resin (A) and the epoxy compound (C) include the following: first, calculating the acid concentration in the polyolefin resin (A); then, mixing the polyolefin resin (A), the epoxy compound (C), and optionally, any other components so that the ratio (R) in the final resin composition is 0.9 or greater; introducing the mixture into a twin-screw extruder; and then melt-kneading the mixture at a temperature of 160 to 280° C., more preferably 180 to 260° C., to obtain a mixture. The resin composition of the present embodiment can then be obtained by impregnating the molten mixture containing the polyolefin resin (A), the epoxy compound (C), and optionally, any other components into a fiber bundle formed by aligning regenerated cellulose fibers (B) in the longitudinal direction after passing through a crosshead die.

[0115] [Molded article and its manufacturing method]

[0116] The molded article of the present embodiment is obtained by molding the above-mentioned resin combination. The molded article of the present embodiment can be obtained by injection molding the above-mentioned resin combination. The molded article of the present embodiment is obtained by molding the aforementioned resin combination, so it has excellent moisture-heat resistance and good mechanical strength.

[0117] In one embodiment, the molded article of this embodiment has a tensile strength retention rate (tensile strength measured in accordance with ISO 527-1, 2) after storage for 50 hours under moist heat conditions of 121°C, 100% RH, and 2 atmospheres ((tensile strength after storage (MPa) / tensile strength before storage (MPa)) × 100 (%)) of preferably 65% ​​or more, more preferably 69% or more, and even more preferably 70% or more.

[0118] [use]

[0119] The molded article obtained from the resin composition of this embodiment has excellent moisture and heat resistance and good mechanical strength. Such a molded article can be suitably used in applications such as housing parts and vehicle door modules.

[0120] Example

[0121] Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following description.

[0122] As raw materials for the resin composition, the following were used.

[0123] <Polyolefin resin (A)>

[0124] Resin (A1): Propylene homopolymer (PP homopolymer, manufactured by SunAllomer Ltd., product name "PMB02A").

[0125] Resin (A2-1): Maleic anhydride-modified polypropylene resin (a2) (product name "MODICP908" manufactured by Mitsubishi Chemical Group Corporation, acid concentration (v1): 0.11 mol / kg).

[0126] Resin (A2-2): Maleic anhydride-modified polypropylene resin (a2) (product name "OREVAC CA 100" manufactured by SK Functional Polymer Co., Ltd., acid concentration (v1): 0.11 mol / kg).

[0127] <Regenerated cellulose fiber (B)>

[0128] Solvent-processed regenerated cellulose fibers (average fiber diameter (long axis) 11 μm).

[0129] <Epoxy Compound (C)>

[0130] Epoxy compound (C-1): epoxidized soybean oil (product name: "Adekacizer O-130P" manufactured by ADEKA CORPORATION, epoxy group concentration (f1): 4.2 mol / kg).

[0131] Epoxy compound (C-2): bisphenol-type epoxy compound (bisphenol A-type epoxy compound (manufactured by Mitsubishi Chemical Group Corporation, product name “jER (registered trademark) 1004K”, epoxy group concentration (f1): 1.0 moL / kg)).

[0132] Epoxy compound (C-3): epoxy group-containing copolymer (ethylene-glycidyl methacrylate=methyl acrylate (manufactured by Sumitomo Chemical Co., Ltd., product name "BONDFAST 7L", epoxy group concentration (f1): 0.2 mol / kg)).

[0133] <Other ingredients>

[0134] Antioxidant (1): Hindered phenol-based antioxidant (manufactured by BASF Japan Ltd., product name "Irganox (registered trademark) 1010").

[0135] Antioxidant (2): a phosphorus-based antioxidant (manufactured by BASF Japan Ltd., product name: "Irgafos (registered trademark) 168").

[0136] Weathering agent: Hindered amine light stabilizer (manufactured by BASF Japan Ltd., product name: "Tinuvin (registered trademark) 111FD").

[0137] [Example 1]

[0138] 66.6% by mass of resin (A1), 2.1% by mass of resin (A2-1), 0.08% by mass of epoxy compound (C-1), 0.21% by mass of antioxidant (1), 0.11% by mass of antioxidant (2), and 0.11% by mass of weathering agent were mixed and fed into a twin-screw extruder. The resulting molten mixture, melt-kneaded at a cylinder temperature of 260°C, was impregnated into a fiber bundle formed by aligning the regenerated cellulose fibers (B) in the longitudinal direction after passing through a crosshead die, so that the regenerated cellulose fibers (B) accounted for 30% by mass. The fiber bundle was then shaped using a shaping nozzle at the exit of the crosshead die, adjusted in shape using a shaping roll, and then cut into 7 mm long pellets using a pelletizer to obtain the resin composition of Example 1. The resin composition had a ratio (R) of 1.4.

[0139] Next, the resin composition (pellets) of Example 1 was injection molded under the following conditions to obtain molded articles (ISO tensile test pieces). The various mechanical strengths of the obtained molded articles were measured under the following conditions. In addition, the wet heat resistance was measured under the following conditions.

[0140] (Molding conditions)

[0141] Molding machine: Made by Shibauramachina Co., Ltd., product name "EC40".

[0142] Test piece: ISO tensile test piece.

[0143] Molding temperature: 200℃.

[0144] Mold temperature: 60℃.

[0145] <Evaluation of Mechanical Strength>

[0146] The obtained ISO tensile test pieces were used to measure tensile strength (TS) and tensile elongation (TE) in accordance with ISO 527-1 and 2. The tensile strength was evaluated according to the following evaluation criteria.

[0147] (Evaluation Criteria)

[0148] Excellent: Tensile strength is 90 MPa or more.

[0149] Good: The tensile strength is 80 MPa or more and less than 90 MPa.

[0150] Not allowed: tensile strength less than 80MPa.

[0151] <Evaluation of Moisture and Heat Resistance>

[0152] The resulting ISO tensile test specimens were stored at 121°C, 100% RH, and 2 atm for 50 hours. The tensile strength was then measured under the same conditions as for the mechanical strength evaluation described above. The tensile strength retention was calculated from the tensile strength (MPa) after the damp heat test and the tensile strength (MPa) before the damp heat test.

[0153] Tensile strength retention (%) = (tensile strength after humidity and heat test (MPa)) / (tensile strength before humidity and heat test (MPa)) × 100

[0154] Furthermore, moist heat resistance was evaluated according to the following evaluation criteria.

[0155] (Evaluation Criteria)

[0156] Excellent: Tensile strength retention rate is 70% or more.

[0157] Good: The tensile strength retention rate is 65% or more and less than 70%.

[0158] Unacceptable: Tensile strength retention is less than 65%.

[0159] [Examples 2 to 5 and Comparative Examples 1 to 6]

[0160] A resin composition was prepared under the same conditions as in Example 1, except that the composition of the resin composition was set as shown in Table 1. A molded article was prepared from the resulting resin composition under the same conditions as in Example 1. Furthermore, the mechanical strength and moist heat resistance of the resulting molded article were evaluated under the same conditions as in Example 1. The results are shown in Table 1.

[0161] [Table 1]

[0162]

[0163] As shown in Table 1, the molded articles of Example 1 to Example 5 obtained by the resin composition satisfying the structure of the present embodiment are excellent in heat and moisture resistance, and the mechanical strength is also good. On the other hand, the mechanical strength of the molded articles of Comparative Example 1 to Comparative Example 3 obtained by the resin composition not containing epoxy compound (C) is good, but the tensile strength retention is low, and the heat and moisture resistance is poor. In addition, the heat and moisture resistance of the molded article of Comparative Example 4 obtained by the resin composition containing epoxy compound (C) and not containing resin (A2) is good, but the mechanical strength is poor. And then, in Comparative Example 5 to Comparative Example 6 where the ratio (R) of the resin composition is less than 0.9, it is still the result of poor heat and moisture resistance.

[0164] From the above results, it is understood that the resin composition of the present embodiment can provide a molded article having excellent moist heat resistance and good mechanical strength.

[0165] Industrial applicability

[0166] The molded article obtained from the resin composition of this embodiment has excellent moisture and heat resistance and good mechanical strength. Such a molded article can be suitably used in applications such as housing parts and vehicle door modules.

Claims

1. A resin composition, characterized in that The resin composition comprises: A polyolefin resin (A) comprising a polypropylene resin (A1) and an acid-modified polypropylene resin (A2), wherein the acid-modified polypropylene resin (A2) is at least one resin selected from a maleic acid-modified polypropylene resin (a1) and a maleic anhydride-modified polypropylene resin (a2), and has an acid concentration (v1) of 0.01 to 0.5 mol / kg as converted to maleic anhydride; regenerated cellulose fibers (B); and Epoxy compound (C) having an epoxy group concentration (f1) of 0.1 to 6.0 mol / kg, The content of the polyolefin resin (A) is 25 to 90% by mass, and the content of the regenerated cellulose fiber (B) is 5 to 70% by mass relative to the total mass of the resin composition. The ratio (R) of the epoxy group concentration in the resin composition to the acid concentration in the resin composition represented by the following formula (1) is 0.9 or more, 2. The resin composition according to claim 1, wherein The resin composition comprises a polyolefin resin-impregnated regenerated cellulose fiber bundle (B1), wherein the polyolefin resin-impregnated regenerated cellulose fiber bundle (B1) is obtained by impregnating a fiber bundle in which the regenerated cellulose fibers (B) are aligned in the longitudinal direction with a mixture of the polyolefin resin (A) and the epoxy compound (C).

3. The resin composition according to claim 1 or 2, wherein The epoxy compound (C) includes at least one compound selected from the group consisting of epoxidized oils and fats, epoxy group-containing copolymers, bisphenol-type epoxy compounds, and epoxysilane compounds.

4. The resin composition according to claim 1 or 2, wherein The ratio of the acid-modified polypropylene resin (A2) to the total mass of the polyolefin resin (A) is 0.5 to 5% by mass.

5. The resin composition according to claim 1 or 2, wherein The content of the polyolefin resin (A) is 25-90 mass %, the content of the regenerated cellulose fiber (B) is 5-70 mass %, and the content of the epoxy compound (C) is 0.05-5 mass % relative to the total mass of the resin composition.

6. The resin composition according to claim 1 or 2, wherein The acid-modified polypropylene resin (A2) includes the maleic anhydride-modified polypropylene resin (a2).

7. The resin composition according to claim 1 or 2, wherein The epoxy compound (C) includes at least one compound selected from the group consisting of epoxy group-containing copolymers and bisphenol-type epoxy compounds.

8. The resin composition according to claim 1 or 2, wherein The average fiber length of the regenerated cellulose fibers (B) in the resin composition is 5 to 30 mm.

9. A molded article of the resin composition according to claim 1 or 2.

10. The method for producing the resin composition according to claim 1 or 2, comprising the following steps: obtaining a mixture of the polyolefin resin (A) and the epoxy compound (C); and compounding the mixture with the regenerated cellulose fiber (B), The operation of obtaining the mixture comprises: The polyolefin resin (A) and the epoxy compound (C) are mixed so that the ratio (R) of the epoxy group concentration in the final resin composition represented by the following formula (1) to the acid concentration in the final resin composition is 0.9 or more.

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